Left-dominant coronary circulation

Case contributed by Matt A. Morgan


Chest pain

Patient Data

Age: 50 years
Gender: Male

Series of images from a coronary CTA, demonstrating left-dominant circulation.

The images show the left circumflex artery eventually supplying the posterior descending artery (PDA), which travels in the posterior interventricular groove from the crux of the heart to the apex (red arrows).  The orange arrows point to obtuse marginal branches of the left circumflex, supplying the posterior aspect of the left ventricle.

Case Discussion

Coronary artery "dominance" is defined in terms of which coronary artery supplies the posterior descending artery (PDA, also known as the "inferior interventricular artery"), and the posterior left ventricular branches. The PDA is the artery that extends along the inferior interventricular groove, from the crux of the heart toward the apex.

Most persons (approx 89.1%) have a "right-dominant" system, which means that the right coronary supplies these arteries.  8.4% of persons have a "left-dominant" system, which means that the left circumflex supplies these arteries (as in our case).

Other variations of dominance exist, such as a "co-dominant" circulation (2.5%) in which the right coronary supplies the PDA and the left circumflex supplies the posterior left ventricle through a left posterolateral branch.

Of note, even with right "dominance," the left coronary artery supplies the majority of the left ventricle.

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